Process of purifying smelter-gases.



'RMNWRDT- I PROCESS 0F PURIFYING SME'JTER GASES;

APPLICATION FILED APB..14, 1908.

kP. DANGKWARDT- PROCESS 0F PURIFYING SMELTER GASES.

APPLICATION FILED APB..14, 1908.

918,424. Patented Apr. 13, 1909.

3 SHEETS-SHEET 2` P. DANGKWARDT.

PROCESS 0F PURIPYING SMELTER GASES.

APPLICATION FILED APB,.14, 1908,

918,424. V Patented Apr. 13, 1909.

3 SHEETS-SHEET 3` T1/wanton .wi-magos I 4 @MM Hof/neg To all whom it may concer/n:

,rAUnD-ANoKWARDT, OFDENVER, ooLoRADo. I

PROCESS OF PURIFYING SMELTER-GASES.

Speciicationof Letters Patent. Application led April 14, 1908. Serial No. 426,977;

Patentednpriiie, 1909.

13e it known that I, PAUL'DANKWARDT, a citizen/,ofthe United States, residing in the cit and county of Denver and State of Colora o, have invented a certain new and useful Process'of Purifying'Smelter-Gases; and I do declarel the followin to be a full,` cleai', and exact description o. the invention, such 'as will enable others skillediin the art tof which it appertains 'to/ make and use the Y,

same, reference being had to the accompanyingdrawings, and to the letters and igures of x of this speciation.

, densing smelter fumes.

reference marked thereon, which forma part My invention relates to a recess` of con- The estructiveness of'- these fumes has been felt 'severely all over the country for a number of years. The principal objectionable ingredients of these fumes being the sulfurous and sulfuric acid, several attempts have been'made to eliminate-these compounds from the gases by converting them into commercial sulfuric acid, but the g'ases being very dilute and there being an insufficient market for the prduct in the localities Wherethe smelters are located, these attem ts `have not been successful.

y present invention consists in a process by which I convert the sulfur compounds into elemental sulfur, which may be shipped to an place and by which the otherconipoun `s are turned into a mixture of gases adapted for heating purposes or for use in pas engines. At the same time I extract the argest part of the heat contained in the gases, by passing them through an a paratus which reduces power in a nove way, thek particu ar process and apparatus for this purpose formingthesubject matter of con-. temporaneous applications, the said applications having'beenled April 14, 1908, and,

`numbered 426978 and 426976 respectively.

.I do not claim any particular apparatus in which the reactionswf this process'niay be made to take place, except that. partv of it which `serves mainly for the conversion of the heat of the gases into useful mechanical Work, which is vcovered by one of the separate applications heretofore referred to.

The accompanyingdrawing illustrates one 'forni of a paratus suited for carrying out the' process t ough it is evident that many other specific constructions may be emplo ed.

In this drawing, Figure 1 is an e'evation showing 'the entire apparatus.4 Fig. 2 is a The same reference characters indicate the same parts in all the views.

Let the numeral 5 designate a gas producer of any type, the same'having an inlet pipe 6 connected with.. the flue dust chamber of a smelter (not shown) and also with a source (not shown) of steam supply.

The numeral 7 designates the ash it of the producer. This producer has an out et pipe 8 whoselower extremity is connected with the lower portion of a precipitating tower 9, composed of ashell orcasingl providedwith a pan 12 at the top which formsacover. The bottom of this pan is perforated as at 4 to allow a spray of solution to fallover the slabs or cross bars 13 and 14 located inside tliegcasing, the two sets of bars being arranged one above another and extending at rightangles to each other, each set being sufficiently separated to allow the solution to pass-downwardly therethrough. Leading into this tower or scrubber, is a i with the ue dust chamber of thesmelter and by means of which the raw fumes are carried to the scrubber.

16 is an outletpipe for the solution, connected with the bottom of the tower 9, and 17 an outlet pipe Afor the gases. Below the outlet pipe 1 6 is a tank 1-8 with which a pump 19 is connected. This pum serves to relmove the li uid fr ornthe tan i 18 and transfer it throug Va pipe 20, to the pan 12 at the top of the tower.

'C is a fan blower which draws the gases of a casing 23 in he lower portion of which is locateda box 24 having a false bottoni 25 which separates a lower compartment 26 from'the body of the box. `Into this coniartment 26 a gas producing medium as cai'- on d-is'ulfid,is introduced through a pipe 27 by means of a punip28 connected by a pipeI 29 with the lower part 30 ol' a pipe condenser 31 having an inlet 32 and an outlet 33 for the cooling water. The carbon disuli'id or other suitable gas-producing medium is introduced to the condenser through a pipe 34. A series of pipes 35 is located within the casing? 23, the said pipes being open ended, their lower extremities communicating with the box 24 pipe 15 which is connected directly v from the preci itating tower and introduces l them by way o a pipe 21, into the bottom'22 ioo 'Land their upper extremities with chamber the compartment 26 and their upper extremi ties protruding into the pipes 35, the pipes 38 being considerably smaller than the pipes 3.5. The lower extremities oil the pipes 38 are fitted closely into openings formed in the falsebottom of the box 24. The box 24, thepipes 3,5 and the lower part of the chamber 36, contain aeirculating fluid preferably water,

j the level of this iluid being indicated by the '20".

dotted line 39 inthe chamber 36'. The gases 'introduced into thebottom 22 o`i` the casing 23, heat the wat-rer other circulating fluid contained in the elements just mentioned, te a temperature below the boiling point. The gasproducing medium delivered to the compartment 2b through the pipe 27, is volatilized by coming in contactwith the heated water, since it boils or volatilizes at a lower temperature than the water. The result is that the solution is set into motion and passing uv wardly through ,the pipes 35,- into the cham er 36, overflows into a conduit 40 and passes downwardly to a turbine motor 41 whence it passes into a box 42 andv thence back through pi es 43 into the box -24 whereby its circu ation is continued.v The gas resulting fronrfthe volatilization of the bisulid of carbon or other gas-pre ducing medium, passes upwardly into the chamber 36 and thence through a pipe 44 back into the condenser 3l and after being condensed therein, is returned again to the circulatingiluid tank where it performs the ,function just described; Any-water carried over Awith the gases from the tower 9 and delivered through the agencyof the pumlp C to the'casing 23,'is condensed within the atter and returned by vway of a pipe 45 to the tank 18, while the gases escaping from the easing 25 after hav,-v

ing served to heat the circulating medium,

v ,pass out of the casing through a port 46, into arcenduit 4'7 whence they pass to thebottom ota precipitating orabsorption tower- 48, ,whlch is et' the same construction' asY the tower 9 heretofore described and has a collecting tank 49 'and a pump 50 from whichtheliquid is taken from the tank 49 and carried through a pipe 60,`to the top of the tower '48 and discharged into ani-,upper tank 51 and passes thence through the perforated Vbottom 52 of the tank 51 downwardly into the tower and through the checker work eon' j, tained therein. In this towerthe gas is puried by the removal of the balance of itsy objectionable elements such as the remain-z dium' as heretofore explained and ar works, where -most of' the solid suspended particles are with-held, vtogether with a sufficient amount of` steam, through the 'producer 5 and through the recipitating tower 9. A'fter passing throughj the blower, these gases are driven into the casing 23 where Athey are utilized to heat a circulating me- J'ter performing the heatingiunction therein, pass through the conduit 47 into the condensing or absorption tower or apparatus 48, from which they are led to any pla-ce where they may be intended to be used. I now start the pumps 19 and 50, which provide for the prope'i` circulation of the solutions to be used in both of the towers' 9 and 48. I/Vhen the water within the circulatingtank composed of the. elements 24, 35 and 36, is put into circulationA in the manner heretofore explained,

it passes through the conduit 40 and operates the turbine 4l.'

The chemical reactions effected in the Various parts of the system in carrying out my improved process are as follows: In the producer 5, the mixture 'of iue gases and steam will leave part of their metallic fumes which will be recovered with the ashes and can be returned to the furnaces. At the same time the glowing carbon with which the producer is filled, reacts with the c'arbonic acid.v reducing this to carbon monoxid according to the formula: (JO2 +C 2CO, while the steam and the sulfurous acid react with the'olowing carh D bon in suchfa way as to form hydrogen suhid and 'carbon monoxid:

so2 +1120 c3 its soo.

It may be stated that it is not necessary to run the gases so slowly as to make this reaction complete, because a certain amount of sulfurous acid ought to be -left undecomposed in the precipitating tower 9. The hot gases on entering. this precipitating tower, ought to be mixed lwith unaltered Hue gas as drawn in through the tube 15, in such aproportion that a slight excess of hydrogen sul- -iid exists over the amount needed for the reaction that isk totale place here. In order to make this reaction perfect, the temperature of the gas mixture has to be reduced considerably, which result is obtained by making it meet a strong shower of solution. This will create a large amount of-steam, The solution I use in the precipitating tower is that otany neutral salt which will not react with the ILS or ,SO2 directly, such as calcium chlorid. If the SO2 and HZS are correctly proportioned, which is vdetermined by a test l it , consists in ,passing the gases together with on the esca ing gas mixture, the following p reaction wi take place:

5 The sulfurset free will settle at the bottom of y tank 18, together with small amounts of dust and metallic fumes, andisjwithdrawn therefrom: at ucertain intervals for further treatment inany of the known ways for the recoverynof the sulfur. 'lhej test fo1``H2S on the escaping gases ought to isiiowal'silight excess of Hand 'no SO2. The gas mixture passes now 'pintogl-fthe hot water turbine' apparatus, wliee" y arge part of its heat is given 0H and transformed into power by putting the circulating medium inthe elements24, 35 and 36, into motion, while the water from the condensed steam returns through the pipe to theatank 18, where it mixes again with the salt" solution to begin its cycle anew.- The gas mixture which contains now only small amounts of hydrogen suld and perha s some ammonia and other nitrogenous sul;- stances, passes on through the conduit47 to the absorption tower 48 where it is brought into contact with the solution of iron salt, the Iobject 'of which is to form iron sullid and ammonium sulfate with the last traces of hydrogen sulfid and the ammonia. When leaving this apparatus, the gas is ready for'use in any way.

Having thus described my invention, whatA .Ivclaim 1s: 'f 1. The process of eliminating the destructive mgredlents from smelter gases, which steam through a body of glowing carbon,

and mixing the resulting gases with further ,iliu'ltities of the original gas-containing suldioxid, after which the gases are brought 1ncontact with a solution containing some i metallic salt which will not react with the gases, cooled, and again washed with a solutlon of an iron salt.

react with the gases to reduce the sulfur compounds to the elemental state, cooling the gases, and nally treating them with a solution of an iron salt.

3. The process of eliminating the destructive `ingredients from sinelter gases, which consists in reducing the sulfur compounds by contact with steam and glowing carbon,

and then reducing the resulting com oundsto the elemental state by bringing t em in contact with further quantities of the original gas, water and a metallic salt which will not react with the gases, condensing the steam formed, and nally washing the gases by a solution of 'an-iron salt. v

4. The process"of'eliminating the destructive ingredients from' smelter gases, which ,consists in transforming the sulfurous acid of thegases into hydrogen suliid by contact withsteam and glowing carbon, and mixing the gases with another quantityof raw gas and reducing' the hydrogen suliid and the sulfurous acid to theelemental state by contact with a solution containing a metallic salt, whichl will not Areact with the gases, cooling, and taking out any excess of h drogen sulfid' and nitrogenous compoun s by ringing the gas mixture in contact with the solution of an iron salt.

In testimony whereof I aflix my signature in'presence of two witnesses.

BAUL n ANoKwARDT.

Witnesses:

DENA NELSON, A. J. OBRIEN. 

